what is the differences between theravada, mahayana, and vajrayana buddhism?

Please help

This page outlines the primary differences between Theravada and Mahayana Buddhism. Vajrayana is generally considered a major sub sect of Mahayana Buddhism - everything on this page that applies to Mahayana, also applies to Vajrayana (see item #13).

http://www.buddhanet.net/e-learning/snapshot02.htm

Wow, that's a HUGE question!!

To get you started, Vajrayana is a part of Mahayana. I don't have a huge amount of experience of the northern schools, so take what I say about them with a pinch of salt . Vajrayana is a set of intense practices designed to shock the consciousness... to 'induce Nirvana'. The philosophy of Vajrayana is basically the same as Mahayana, in that we all have Buddha-nature, the nature of 'reality', things like that. Zen and Pure Land are two big Mahayana schools. The main aim of Mahayana seems to be attainment of the Bodhisattva ideal... which is different (on the surface) to the Theravada aim.

Theravada, on the other hand, takes its teachings directly from the Pali Canon and commentaries (the oldest recorded Buddhist teachings, much of which is directly attributed to the Buddha). The aim is the attainment of Nibbana.

That should get you started

The reform of "Greater Vehicle" and "Lesser Vehicle" in Buddhism are briefly contrasted and compared in the section, ?Buddhist Qigong and Buddhism?, of the Zhuan Falun Lecture on the web:
http://www.falundafa.org/book/eng/pdf/zfl_new.pdf

The basic Buddhist belief is well explained in the 'Falun Gong' book. Advanced practices are discussed in details in the Zhuan Falun Lecture. Both books and meditation demonstration video are free to download from the URL listed below. If you need any help, contact a local practitioner in your area for free instructions.

Falun Gong was found in 1992 by Master Li Hongzhi in China. About 100 million followers like the practice in over 80 countries worldwide. Falun Gong is an ancient practice for the body, mind, and spirit based upon the universal principles of Truthfulness, Compassion, and Tolerance. Falun Gong consists of five sets of powerful exercises.

Falun Gong, Tibetans, other Buddhists, and Daoists have been persecuted in China. The most offensive human right violation is the organ harvesting from the Falun Gong practitioners in China. Can you kindly sign a petition to stop persecution of Falun Gong practitioners in China, please ?
http://cipfg.org/en/news/petition.html